Field of the Invention
The present invention relates to a stage apparatus which moves while a slide is placed thereon and a microscope equipped with the stage apparatus.
Description of the Related Art
Recently, an optical microscope has been used by pathologists for pathological diagnosis as a means for implementing fine observation of a tissue segment of a lesion. When microscope examines, a slide glass on which an observation target is placed is placed on a stage for a microscope, and the stage is moved to locate the observation region immediately below an objective lens (observation visual field). When performing microscopic observation, it is necessary to move a measurement region by a very small dimension with high precision, as needed. In order to meet such a requirement, a stage apparatus for a microscope is formed from an XY stage so as to be capable of arbitrarily moving in two-dimensional directions and is required to implement high-precision observation position management on the XY stage mounted on the microscope.
Japanese Patent Laid-Open Nos. 2013-64731 and 2013-7718 disclose techniques associated with positioning element techniques for XY stages and designed to hold a scale used for a linear encoder or the like with high precision in one direction in which measurement is performed.
In the arrangement of an XY stage to which a plurality of members having different linear expansion coefficients are integrally fixed, however, when a temperature change occurs, thermal expansions cause fine expansion/contraction (thermal drift) between a plurality of members. The thermal expansion/contraction difference between the respective members causes stress in the fixed portion of each member. This can cause distortion in each member of the XY stage in the X and Y directions. The influence of distortion on a glass scale for observation position management of the XY stage can make it difficult to implement high-precision observation position management on the XY stage.
Japanese Patent Laid-Open Nos. 2013-64731 and 2013-7718 each disclose an arrangement for holding a glass scale with high precision in one direction in which measurement is performed, but give no consideration to an arrangement for suppressing the influence of expansion/contraction (thermal drift) caused by thermal expansion. That is, Japanese Patent Laid-Open Nos. 2013-64731 and 2013-7718 each give no consideration to an arrangement for suppressing the occurrence of distortion caused by expansion/contraction caused in members by thermal expansion.
The present invention has been made in consideration of the above problem, and provides a stage apparatus which can implement high-precision observation position management by suppressing the occurrence of distortion by the expansion/contraction of members caused by thermal expansion.